The archives of this site should cover it, in particular this very "Grading Debate" sub-forum.
It wasn't an issue that was ever put to the vote at an ECF Council meeting.
The ECF, or perhaps just its directors, were talked into believing that the grading system needed recalibration. AS a consequence, the median and mode grades moved from the 110 to 120 zone up to the 130-140 zone.
Did no-one raise a couple of apparent recent anomalies? These being the curious case of the late and reversing finishing order in the Grand Prix and the strangeness of the timing and language surrounding the appointment of the Development Officer?